Subject: Re: [PATCH v2 1/2] media: dt-bindings: media: xilinx: Add Xilinx MIPI CSI-2 Rx Subsystem

From: Hyun Kwon <[email-masked]>
Date: Fri, 25 Jan 2019 18:14:46 -0800

Hi Vishal,

Thanks for the patch.

On Fri, 2019-01-25 at 09:52:56 -0800, Vishal Sagar wrote:
> Add bindings documentation for Xilinx MIPI CSI-2 Rx Subsystem.
> 
> The Xilinx MIPI CSI-2 Rx Subsystem consists of a CSI-2 Rx controller, a
> DPHY in Rx mode, an optional I2C controller and a Video Format Bridge.
> 
> Signed-off-by: Vishal Sagar <[email-masked]>
> ---
> v2
> - updated the compatible string to latest version supported
> - removed DPHY related parameters
> - added CSI v2.0 related property (including VCX for supporting upto 16
>   virtual channels).
> - modified csi-pxl-format from string to unsigned int type where the value
>   is as per the CSI specification
> - Defined port 0 and port 1 as sink and source ports.
> - Removed max-lanes property as suggested by Rob and Sakari
> 
>  .../bindings/media/xilinx/xlnx,csi2rxss.txt        | 105 +++++++++++++++++++++
>  1 file changed, 105 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt b/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt
> new file mode 100644
> index 0000000..98781cf
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt
> @@ -0,0 +1,105 @@
> +Xilinx MIPI CSI2 Receiver Subsystem Device Tree Bindings
> +--------------------------------------------------------
> +
> +The Xilinx MIPI CSI2 Receiver Subsystem is used to capture MIPI CSI2 traffic
> +from compliant camera sensors and send the output as AXI4 Stream video data
> +for image processing.
> +
> +The subsystem consists of a MIPI DPHY in slave mode which captures the
> +data packets. This is passed along the MIPI CSI2 Rx IP which extracts the
> +packet data. The Video Format Bridge (VFB) converts this data to AXI4 Stream
> +video data.
> +
> +For more details, please refer to PG232 Xilinx MIPI CSI-2 Receiver Subsystem.
> +
> +Required properties:
> +--------------------
> +- compatible: Must contain "xlnx,mipi-csi2-rx-subsystem-4.0".
> +- reg: Physical base address and length of the registers set for the device.
> +- interrupt-parent: specifies the phandle to the parent interrupt controller
> +- interrupts: Property with a value describing the interrupt number.
> +- clocks: List of phandles to AXI Lite, Video and 200 MHz DPHY clocks.
> +- clock-names: Must contain "lite_aclk", "video_aclk" and "dphy_clk_200M" in
> +  the same order as clocks listed in clocks property.
> +- xlnx,csi-pxl-format: This denotes the CSI Data type selected in hw design.
> +  Packets other than this data type (except for RAW8 and User defined data
> +  types) will be filtered out. Possible values are as below -
> +  0x1E - YUV4228B
> +  0x1F - YUV42210B
> +  0x20 - RGB444
> +  0x21 - RGB555
> +  0x22 - RGB565
> +  0x23 - RGB666
> +  0x24 - RGB888
> +  0x28 - RAW6
> +  0x29 - RAW7
> +  0x2A - RAW8
> +  0x2B - RAW10
> +  0x2C - RAW12
> +  0x2D - RAW14
> +  0x2E - RAW16
> +  0x2F - RAW20
> +- xlnx,vfb: This is present when Video Format Bridge is enabled.

Isn't this optional as well?

> +
> +Optional properties:
> +--------------------
> +- xlnx,en-csi-v2-0: Present if CSI v2 is enabled in IP configuration.
> +- xlnx,en-vcx: When present, there are maximum 16 virtual channels, else
> +  only 4. This is present only if xlnx,en-csi-v2-0 is present.
> +- xlnx,en-active-lanes: Enable Active lanes configuration in Protocol
> +  Configuration Register.
> +- xlnx,cfa-pattern: This goes in the sink port to indicate bayer pattern.
> +  Valid values are "bggr", "rggb", "gbrg" and "grbg".
> +
> +Ports
> +-----
> +The device node shall contain two 'port' child nodes as defined in
> +Documentation/devicetree/bindings/media/video-interfaces.txt.
> +
> +The port@0 is sink port and shall connect to CSI2 source like camera.
> +It must have the data-lanes property. It may have the xlnx,cfa-pattern
> +property to indicate bayer pattern of source.

These two properties better be spelled out properly. Maybe better to mention
the data-lanes is from video-interfaces.txt.

Thanks,
-hyun

> +
> +The port@1 is source port could be connected to any video processing IP
> +which can work with AXI4 Stream data.
> +
> +Both ports must have remote-endpoints.
> +
> +Example:
> +
> +	csiss_1: csiss@a0020000 {
> +		compatible = "xlnx,mipi-csi2-rx-subsystem-4.0";
> +		reg = <0x0 0xa0020000 0x0 0x10000>;
> +		interrupt-parent = <&gic>;
> +		interrupts = <0 95 4>;
> +		xlnx,csi-pxl-format = <0x2a>;
> +		xlnx,vfb;
> +		xlnx,en-active-lanes;
> +		xlnx,en-csi-v2-0;
> +		xlnx,en-vcx;
> +		clock-names = "lite_aclk", "dphy_clk_200M", "video_aclk";
> +		clocks = <&misc_clk_0>, <&misc_clk_1>, <&misc_clk_2>;
> +
> +		ports {
> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +
> +			port@0 {
> +				/* Sink port */
> +				reg = <0>;
> +				xlnx,cfa-pattern = "bggr"
> +				csiss_in: endpoint {
> +					data-lanes = <1 2 3 4>;
> +					/* MIPI CSI2 Camera handle */
> +					remote-endpoint = <&camera_out>;
> +				};
> +			};
> +			port@1 {
> +				/* Source port */
> +				reg = <1>;
> +				csiss_out: endpoint {
> +					remote-endpoint = <&vproc_in>;
> +				};
> +			};
> +		};
> +	};
> -- 
> 2.7.4
> 

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